Question And A Puzzle

[Guest Ant]

Hi guys,

 

Firstly a question - does anyone know the current rating of the two red wires which go from the battery to the fusebox?

 

Why ask that ... well ... I have a junction in one of mine (don't ask why - it seemed like a good idea at the time!) but I've managed to melt my plastic around my "chocolate block" connector by driving in the rain with the heater, wiper and lights on. Doh. I now want to get another length of wire and some suitably rated connections for it to replace the piece between the junction and the battery, and get a suitably rated junction box.

 

And now for the puzzle ... parked the car up after driving in the rain, and hte wipers were half way up the screen. Came back to it 5 hours later, put the ignition on, and the wipers started (as expected), but my radiator fan came on too. Most bizaar because this works of a separate fuse and relay wired in to the junction in the wire mentioned above. I turned the wipers off but the fan stayed on. Then I tried to start the car, but ignition 3 was dead. Thought "Oh, I must have blown a fuse", checked the fuses one by one - all fine. Then I put the ignition on again and the fan didn't come on, and the car started fine. Wipers still working fine too, and fan all ok as well. Any ideas?

[Longboarder]

I suspect you have an intermittent poor/non-existent type connection in the offending junction box (high resistance generating enough heat to melt the plastic) and that led to an odd reverse feed from the fuse box back through the fan circuit but not enough to run the ignition. As often happens switch off/on again and it takes a different path.

If you have two feeds from battery to fuse box I would suggest 3mm or even 4mm sq wire for both and any joins should be soldered. Personaly I would steer clear of chocolate box connectors in cars and finaly find a better place to supply the fan from, i.e. via the fuse box.

 

Nigel

[Guest TerryBarry]

I assume that these are the two red leads with the fusible links at the battery end.

I shortened mine and soldered them back together.

From a bit I removed I reckon that they are 85 strands x 0.28mm

The closest Vehicle Wiring Products list to this is 84x0.30mm rated as 50A in thinwall and 42A in standardPVC insulation.

Terry

[Guest Ant]

Thinking about it, that's why I put the junction box in - I wanted to shorten them and keep the original terminals and fuse links, but I had trouble soldering them back together because the heat went down the wire rather than melting the solder. Hence the need for a junction.

 

Right - I'm off to vehicle wiring products tomorrow lunch time so I'll see what they do in the junction box / fusable link wire department.

 

cheers all

 

Ant

 

PS - Typical really - drove in every day last week, in the rain, and now it's sunny again I've got a melted wiring block! Hopefully tomorrow will sort it.

[Guest dajimmy]

This tip might help.When soldering large wires,use long nose pilers with elastic bands around the handles, cliped on to the wire.This stops the heat traviling down the wire so quickly. You can use on smaller wire, but some times crushs the wire.Hope this helps.

[Jon Bradbury]

My solution to soldering fat wires (eg, the +ve feed from the alternator to the battery) is to use a heat gun. The resultant joint is untidy but it works.

 

Of course, what I should have done was shorten it from the battery end...